Numerous medical devices exist today, including but not limited to electrocardiographs (“ECGs”), electroencephalographs (“EEGs”), squid magnetometers, implantable pacemakers, implantable cardioverter-defibrillators (“ICDs”), neurostimulators, electrophysiology (“EP”) mapping and radio frequency (“RF”) ablation systems, and the like. Implantable medical devices (hereafter generally “implantable medical devices” or “IMDs”) are configured to be implanted within patient anatomy and commonly employ one or more leads with electrodes that either receive or deliver voltage, current or other electromagnetic pulses (generally “energy”) from or to an organ or tissue (collectively hereafter “tissue”) for diagnostic or therapeutic purposes.
Typically, each lead of a medical device is securely anchored to a portion of patient tissue through sutures. Separate and distinct suture sleeves are generally slid over the leads to suitable areas for anchoring to the patient tissue. Once a suture sleeve is positioned at a desired area, a medical professional, such as a surgeon, securely connects the sutures to the patient tissue and ties the ends of the sutures around the suture sleeve.
The suture sleeve protects the lead from being damaged. For example, if no suture sleeve were used, the force of tying the suture around the lead could crush or otherwise damage the conductors within the lead. The suture sleeve protects the lead from the compressive or crushing force exerted by the suture tie. Also, the suture sleeve is intended to grip an outer surface of the lead with sufficient traction to prevent the lead from slipping or otherwise moving within the suture sleeve. However, it has been found that in certain instances leads may be susceptible to slipping within the suture sleeve. Lead slippage within the suture sleeve typically dislodges the lead from an anchoring site, and may result in loss of therapy. Additional surgery is then needed to reposition and anchor the lead.
Because of the possibility of lead slippage within a suture sleeve, many medical professionals prefer to tie the sutures to the suture sleeves with an excessive amount of force. In doing so, however, the increased force of the suture ties may pinch the lead body, and damage the underlying components of the lead. Indeed, with enough force, the suture sleeve itself may even split open.
Further, because the suture sleeves are separate and distinct components from the leads themselves, the suture sleeves are manufactured separately and distinctly from the lead body, thereby adding to the cost of the lead and device assembly. Also, as noted above, during surgery, before anchoring the leads to patient tissue, a surgeon first must slide the suture sleeves over the leads, and then position each suture sleeve to a desired position, thereby adding to the duration of the procedure. Accordingly, the use of suture sleeves generally leads to increased manufacturing and surgical time and cost.
Additionally, leads often fail due to abrasion. For example, a lead may rub against a device, such as a can of an implantable medical device, another lead, calcified patient tissue, or the like. Further, the lead itself may be pinched between a device and patient anatomy, or even between patient anatomy, such as between bones proximate to a collar bone and/or shoulder of an individual. The pinching may crush or otherwise damage components of the lead.
In order to protect against the harmful effects of lead abrasion or crushing, some leads are manufactured with additional layers of material. However, with each additional layer of material, the leads become stiffer. With increased stiffness, the lead body may be difficult to articulate and navigate through patient anatomy. Moreover, a stiff lead may damage patient anatomy. For example, a stiff lead may perforate vasculature.